Field of the Invention
The present invention relates to a development device employing an electrophotographic system or an electrostatic recording system used as a copying machine or a printer, a process cartridge, and an image forming apparatus.
Description of the Related Art
Conventionally, a contact development system has been employed as a system for developing a latent image in an electrophotographic apparatus such as a printer or a copying machine. In the contact development system, development is performed with an image bearing member (hereinafter referred to as a photosensitive drum) and a developer bearing member (hereinafter referred to as a development roller) contacting each other. The contact development system can produce a high-quality image output, and thus many image forming apparatuses based on this system have been proposed.
Some contact development systems include a configuration in which a photosensitive drum and a regulation member (hereinafter referred to as a development blade) rotate while in contact with a developer roller. In this configuration, the development roller may rotate with no coating of a developer (hereinafter referred to as toner) in an assembling process or in a situation of first-time use, for example. When the development roller rotates, sliding friction between the development roller and each of the photosensitive drum and the development blade occurs so that the surfaces of the development roller, the development blade, and the photosensitive drum are scratched, which may affect an image quality. To deal with such a problem, a configuration has been proposed in which a lubricant is previously borne on a surface of a development roller, as in Japanese Patent Application Laid-Open No. 2004-264428.
However, there still remains a problem in an apparatus in which an end seal contacts an end of the development roller for the purpose of preventing leakage of toner in a development container. The development roller contacting the end seal is not coated with the toner or the lubricant. Accordingly, when the end seal or the photosensitive drum slides relative to the development roller, the surface of the development roller may be cracked or scratched, and the toner may leak out via cracks or scratches.
To address this, means for previously applying a lubricant to an end seal has been discussed, as in Japanese Patent Application Laid-Open No. 2005-181713. However, the lubricant is conveyed from the end seal to a photosensitive drum via the development roller, so that there is no or very little lubricant remaining on the development roller. In such a state, when the end seal or the photosensitive drum slides relative to the development roller, as described above, a surface of the development roller may be cracked. Particularly, since prolonging of an apparatus life has been recently required, the possibility has increased that a lubricant amount remaining on the development roller decreases in the apparatus life.